The stand-off between India and Bhutan on one side and China on the other at Doklam, a tri-junction once between India, Tibet and Bhutan, and the larger border dispute between the two Asian giants, have their origins in the British invasion of Tibet in 1904.
At the turn of the 20th century, the geopolitical balance between a crumbling Manchu empire and India was massively in favour of British India. Those were the days of the Great Game, a contest to gain influence from Iran to Tibet, played out between British India and an expanding Tsarist Russia. It was to ward off any perceived Russian influence in Tibet that Lord Curzon dispatched Colonel Younghusband on what the British called their Tibet ‘expedition’.[Source]